'#1823: add a better error message if FFmpeg is not found on PATH

iped-engine/src/main/java/iped/engine/task/transcript/WhisperTranscriptTask.java

@@ -7,6 +7,7 @@
 import java.io.InputStreamReader;
 import java.util.Arrays;
 import java.util.List;
+import java.util.concurrent.atomic.AtomicBoolean;
 
 import org.apache.commons.lang3.SystemUtils;
 import org.apache.logging.log4j.LogManager;
@@ -15,6 +16,8 @@
 import iped.configuration.IConfigurationDirectory;
 import iped.engine.config.AudioTranscriptConfig;
 import iped.engine.config.Configuration;
+import iped.engine.config.ConfigurationManager;
+import iped.exception.IPEDException;
 
 public class WhisperTranscriptTask extends Wav2Vec2TranscriptTask {
 
@@ -24,6 +27,20 @@ public class WhisperTranscriptTask extends Wav2Vec2TranscriptTask {
     private static final String LIBRARY_LOADED = "library_loaded";
     private static final String MODEL_LOADED = "model_loaded";
 
+    private static final AtomicBoolean ffmpegTested = new AtomicBoolean();
+
+    @Override
+    public void init(ConfigurationManager configurationManager) throws Exception {
+        if (!ffmpegTested.getAndSet(true)) {
+            try {
+                Runtime.getRuntime().exec("ffmpeg");
+            } catch (IOException e) {
+                throw new IPEDException("Error checking FFmpeg presence, is it on PATH?");
+            }
+        }
+        super.init(configurationManager);
+    }
+
     @Override
     protected Server startServer0(int device) throws IOException {
         if (numProcesses != null && device == numProcesses) {